title: What factors explain the differences in morbidity estimations among general practice registration networks in the Netherlands? A first analysis.
abstract: BACKGROUND
  Information on the incidence and prevalence of diseases is a core indicator for public health. There are several ways to estimate morbidity in a population (e.g., surveys, healthcare registers). In this paper, we focus on one particular source: general practice based registers. Dutch general practice is a potentially valid source because nearly all non-institutionalized inhabitants are registered with a general practitioner (GP), and the GP fulfils the role as "gatekeeper". However, there are some unexplained differences among morbidity estimations calculated from the data of various general practice registration networks (GPRNs).
  
  
  OBJECTIVE
  To describe and categorize factors that may explain the differences in morbidity rates from different GPRNs, and to provide an overview of these factors in Dutch GPRNs.
  
  
  RESULTS
  Four categories of factors are distinguished: "healthcare system", "methodological characteristics", "general practitioner", and "patient". The overview of 11 Dutch GPRNs reveals considerable differences in factors.
  
  
  CONCLUSIONS
  Differences in morbidity estimation depend on factors in the four categories. Most attention is dedicated to the factors in the "methodology characteristics" category, mainly because these factors can be directly influenced by the GPRN.
authors.affiliation: National Institute for Public Health and the Environment, RIVM, Bilthoven, the Netherlands. karin.van.den.dungen@rivm.nl
authors.forename: Catharina
authors.initials: C
authors.lastname: van den Dungen
authors.forename: Nancy
authors.initials: N
authors.lastname: Hoeymans
authors.forename: Ronald
authors.initials: R
authors.lastname: Gijsen
authors.forename: Marjan
authors.initials: M
authors.lastname: van den Akker
authors.forename: Jos
authors.initials: J
authors.lastname: Boesten
authors.forename: Henk
authors.initials: H
authors.lastname: Brouwer
authors.forename: Hugo
authors.initials: H
authors.lastname: Smeets
authors.forename: Willem Jan
authors.initials: WJ
authors.lastname: van der Veen
authors.forename: Robert
authors.initials: R
authors.lastname: Verheij
authors.forename: Margot
authors.initials: M
authors.lastname: de Waal
authors.forename: Francois
authors.initials: F
authors.lastname: Schellevis
authors.forename: Gert
authors.initials: G
authors.lastname: Westert
mesh_terms: D005194:Family Practice; D006801:Humans; D038801:International Classification of Diseases; D009017:Morbidity; D009426:Netherlands; D012042:Registries